The present invention pertains to two-way communications systems, such as might be utilized between an airplane and a guided missile, or similar circumstances. Generally, in this type of system a control unit includes a transmitter and receiver and a remote unit includes a transmitter and receiver with the receiver of the remote unit being designed to lock onto the transmitter of the control unit and the receiver of the control unit being designed to lock onto the transmitter of the remote unit. When the remote unit is located on a missile or projectile approaching a target, jamming signals from the target may be strong enough to make it difficult for the remote receiver to recognize and lock onto a transmitted signal from the control unit. Further, it is essential that the two transmitter/receiver loops be locked or synchronized in the shortest possible time.